Actuating mechanism for contact and blast valve unit

ABSTRACT

Operating arrangement for synchronous actuation of a blast valve and main contact of the gas-insulated circuit breaker. The arrangement provides a close coupled high speed blast valve actuating arrangement which is external of the high pressured gas chamber and has means for releasing the blast valve while the operating mechanism is still connected to the main contact.

United States Patent Goodwin, Jr.

[ Dec. 3, 1974 1 1 ACTUATING MECHANISM FOR CONTACT AND BLAST VALVE UNIT [75] Inventor: Edwin C. Goodwin, Jr., Canton,

Mass.

[73] Assignee: Allis-Chalmers Corporation,

Milwaukee, Wis.

22 Filed: July is, 1973 [21] Appl.No.:380,250

[52] US. Cl 200/148 F, 200/148 B, 200/145 [51] Int. Cl. H0111 33/42 [58] Field of Search 200/148 B, 148 R, 148 F,

[56], References Cited UNITED STATES PATENTS 3,214,545 10/1965 Cromer ..200/148B Leeds 200/148 R Floessel 200/148 R Primary Examiner-Robert S. Macon Attorney, Agent, or FirmR0bert C. Jones 5 7 ABSTRACT Operating arrangement for synchronous actuation of a blast valve and main contact of the gas-insulated circuit breaker. The arrangement provides a close coupled high speed blast valve actuating arrangement which is external of the high pressured gas chamber and has means for releasing the blast valv'e while the operating mechanism is still connected to the main contact.

12 Claims, 4 Drawing Figures PATENTEL DEC 3l974 sum 3 nr 3 to provide a separate operator for actuating the main contact and another separate operator forv operating the blast valve mechanism. In providing the separate operators a timing device is necessary to provide the necessary timing synchronism between the operation of the contact and the operation of the blast valve. This type of an arrangement has been somewhat satisfactory for installations where space is not at a premium. However, in modern circuit breaker installations such as in a compact substation'arrangement in which compactness is one of the factors of design,- all internal mechanism must be as simple and trouble free as possible. This is especially true of circuit breakers utilizing a two pressure system which is sealed in a-relatively compact enclosure.

SUMMARY OF THE INVENTION In accordance with a preferred embodiment of the invention there is providedan operating mechanism for effecting the opening movement by main contact and in synchronism therewith foropening a blast valve. The

i the contact and blast valve operating mechanism; and

opening of the blast valve is effected prior to the comfree to move to a closed position while the movable contact is being moved to a fully-open position. The operating mechanism further serves to move the main movable contact to closed position without actuating the blast valve-Thus, the operating mechanism is effective through a complete cycle and the blast valve is conditioned for operation prior to-the closing movethem of the main movable contact. This arrangement insures that the blast valve is open a sufficient time to effect are interruption consistent with econo'micuse of 7 high pressure gas and is always operative and readyvto FIG. 4 is a fragmentary view in rear elevation showing the supporting frame structure and the operating linkage.

DESCRIPTION OF THE INVENTION Referring to FIG. I, there is shown an enclosed gasinsulated circuit breaker or interrupter 10. The interrupter 10 is enclosed in a gas tight enclosure tank 11. Within the tank 11 there is supported a central housing 16 which is operatively supported in depending relationship from a central insulating pipe 17 that is secured to. an upper mounting flange bracket (not shown). The central housing 16 is metallic and serves both as a support and as a conductor for a pair of contact and blast valve units 18 and 19.

The contact and blast valve units 18 and 19 are identi'cal and thus a description of the unit 18 will also apply to the unit 19. As shown, the contact in blast valve unit l8-comprises an insulating contact housing 21 which is supported incantilever'style by a mounting frame 22 that is bolted in electrical and secured relationship to the central housing 16. As viewed in FIG. 1, the leftwardextending' end (not shown) of the housingZl includes the mounting plate (not shown) towhich a rightwardlyaxially extending tubular stationary contact 23 is secured. In the rightwardly extending end of the contact 23 there is provided a hollow stationary structure of resilient contact fingers 24 which are adapted to receive the end of a tubular axially movable contact 26. The axially movable main contact 26 is supported for axial movement in a tubular supporting nozzle-27 which is integrally formed as a part of the-supporting frame 22. Surrounding the supporting nozzle 27 is a cir-, cular gas passage 28 which has communication with a 1" I circular gas passage 29 formed in the supporting frame provide a blast of high pressure gas to the contacts before they separate to extinguish the are that is established betweenthe contacts. The operating mechanism is further particularly well suited for confined close coupled arrangements. The configuration, structure,

placement and function of themain contact and blast valve actuating mechanism isoperable to obtain high speed breaker operation in combination with adequate gas flow and permits back-to-back mounting for dual contact operation.

DESCRIPTION OF THE DRAWINGS 22. The supporting frame 22 has an angularly, downwardly extending portion 31. in which a U-shaped gas passage 32 is formed and which communicates with the circular passage 29.

An elbow member 33 is secured to the bottom mounting surface 34 of the, frame 22. The opposite end of the elbow 33 mateswithin sealed relationship on an outlet 36 of a T-shaped header 37 which operates to distribute highpressure gas to the units 18 and 19.

Within the elbow 33'there is operatively supported a blast valve '38- which is biased to closed position by means of a compression spring 39. The blast valve .38 isadapted to be moved axially downwardly to allow a blast of high pressure gas to flow from the elbow into the passages 32 and 29 and thus to the passage 28 to be directed thereby to the area 42 to extinguish the are established between the movable contact 26 and stationary contact 24 upon the contact.

Gas at a relatively high pressure is supplied to the elbow through the distribution header 37 via asupply pipe 43 which engages a flange 44 of the header 37. A supply of gas is available to the supply pipe 43 from a high pressure tank (not shown) that is in communication with the lower end of the supply pipe 43 and which issupported by the housing 11.

As previously mentioned, the movable contact 26 is moved to an open position in synchronism. with the opening of the blast valveu38. Thus, when the contact opening movement of the Y 26 is moved to a position where it is just about to separate from the resilient fingers 24, the blast valve 38 is opened to'allow a blast of high pressure gas to flow to the area 42 so that the high pressure gas is available at the instant the movable contact 26 separates from the resilient fingers 24 to thereby establish an are so that the gas can extinguish the arc. I v

Axial movement of the contact 26 to open and closed positions relative to the contact 24 and, similarly, operation of the contact 25 associated with the contact and blast valve unit 19 is effected by the linkage operators 48 and 49, both of which are actuated simultaneously by means of the movable operating rod 51. Both of the operating linkages 48 and 49 are identical; therefore, a description of the operating linkage 48 and the associated contact 26 will also apply to the operating linkage 49 associated with the contact and blast valve unit formed on the elbow 33 by screws which extend through flanges 61 and 62 of the side frames 57 and 58 threadedlyengage in the mounting pad. The a'rcuate crank 54 has integrally formed therewith a pair of spaced arms 64. The free ends of the pair of spaced arms 64 receive between them the end of an adjustable tying link 66 which is connected tothe arms by means member 71 engages against a tongue portion 79 of a latch 81.The tongue portion 79 is supported for axial movement in a latch body 82 and is urged outwardly therefrom by means of a spring 83. The Spring 83 is re- 'tained in position by means of a threaded nut 84. The

latch body 82 is provided with two vertically spaced apart arms 86 and 87 which are pivotally mounted on the pin 73 on which the cam 71 is also mounted. Thus, as the cam member 71 is pivotally moved ina clockwise direction, the vertical cam face 78' will engage against a vertical surface 91 formed on the latch tongue .79, thereby forcing the latch body 82 to pivot about the end of the rod 94 is pivotally connected to the rightof a pin 67. As shown, *the tie link 66 is pivotally atment of the tie links 66 and 66A thereby pivoting the arcuate cranks 54 about the rod 56 in a clockwise direction and the pivotal movement'of the a rcuate crank 54A about its rod 56A in a counterclockwise direction, as viewed in-F1031. The pivotal movement of thecranks 54 and 54A as described will effect withdrawal or opening movement of the contacts 26 and 25, re-

spectively. j v i Aspreviously mentioned, the operators 48 and 49 also effect the synchronous operation ,of the blast valve 38 and the blast valvev38A in timed relationship to the opening move ment of the contacts 26 and 25, respectively. To effect the timed opening movement of the blast valve 38, there is provided a cam member 71 that is pivotally mounted on a pin 73 that is carried in the side frames 57 and 58. The cam member 71 is provided with an arm portion 74 that pivotally receives the end of an adjustable tie link 76. The opposite end of the tie link 76 is pivotally secured to a pin 77 that extends through the spaced apart arms 64 of the arcuate'crank 54. Thus, as the crank 54 is moved in a clockwise direction, the arms 64 ,will move with it in the same direction, thereby effecting the ,pivotal movement of the cam member 71 about the pin, 73 in a clockwise direction. Asthe cam member 71 pivots in a clockwise direction, a vertical cam face 78 formed on the cam wardly extending endof an arm of a lever 100 that is pivotally secured by a pin '97'to a boss 9 8 integrally formed with the mounting base99 to which the elbow 33 "is secured. The leftwardly extending end of the lever 100', as viewed-in FIG. 2, is pivotally connected to a valve actuating rod'lOl. As shown, the rod 101 extends through the bottom portion of the mounting base .99, of

. of the lever 100 about the pin 97 is effected by the pivotal movement of the latch body 82 in a'clockwise direction. The clockwise pivotal movement of the latch body 82 imparts an upwardmovement to the rod 94, thereby effecting the pivotal movement of the lever 100 about pin 97. This movement of the lever 100 will cause the pin 101 to move downwardly and to engage the blast valve 38 to thereby open passage 41 allowing gas at a relatively high .pressureto flow into the passages 32, 29, 28 tothearc gap area 42. I j As previosuly mentioned, the'blast valve 38 must be allowed to close after a blast-of gashas been delivered tothe arcing area 42 and prior to the complete with drawal of the movable contact to its fully open position, as depicted in FIG. 2. To 'effect a release of the blast valve 38 while-stillmaintaining' the-rightward withdrawalmovement of the contact 26, adisengaging means. is' provided "vvhich is operative to release the latch body 82 from the operating linkage. To this end, as the latch body 82 moves ina clockwise direction, as viewed in FIG. 3, the tongue portion 79 thereof stops against a cam surface 106 until such time as the corner 107 of the tongue portion of the latch 79 engages horiclined arm portions 114 and 116, respectively. The arm portions 114 and 116 are held stationary by'meansof a transversely extending pin 1 17 that engages in a vertical groove 118 formedin a fixed abutment 119 on the supporting structure 59. Thus, as the corner 107 of the and 116 by operation of the pin 117 restrain the fixed cams 111 and 112 from rotating. Thus, as the cam member 71 is continued in its rotary. motion about the 'pin 73 in a clockwise direction, the latch body 82 moving with the cam 71 will forcefully engage the corner portion 107 of the tongue 79 against the surfaces 108 and 109, thereby forcing the latch tongue 79 inwardly against the pressure of the spring 83. As the'rotation of the latch body 82 continues in a clockwise direction, the latch tongue 79 will be moved inwardly further into the latch body 82 until such time as a trailing cam surface 120 moves over the top surface of the tongue por tion 79 of the latch so that the tongue 79 rides on the surface 120. With this condition obtained, a tension spring 121, FIGS. 2 and 3, urges the arm 100 to pivot about the pin 97 in a clockwise direction, thereby lifting the pin 101 free of the blast valve 38 to release the blast valve so that the spring will return the valve 38 to its closed position. This condition is obtained because the tongue 79 now rides on the cam surface 120-and thus under the urgency of the spring 121, the latch body 82 will return to itsoriginal position, depicted in FIG. l.-As the latch body '82 is forcefully returnedato.

will be free to reset to closed position for subsequent operation. I I

When the rod 51 is moved downwardly, the arcuate crank 54 is caused to pivot in the counterclockwisedirection about the pin 56,-the'reby' moving the cam member 71' in a counterclockwise "direction. As the 1. A circuit breaker of the fluid-blast type including a stationary contact;

a movable contact separable from saidstationary contact to establish an arc;

a source of fluid under pressure; 1

a blast valve operably connected between said source of fluid under pressure and the area where an arc is drawn between said contacts, said blast valve being normally biased to a closed position, and operable when mechanically actuated to an open position to direct a blast of fluid under pressure to the area of arcing;

a frame;

a rocker arm pivotally supported by said frame;

a blast valve engaging rod carried by said rocker arm in position to engage and'displace said blast valve to an open position when said rocker arm is pivoted in one direction;

operating linkage means operably connected to move said movable contact to open position;

a pivotal latch member operably connected to said rocker arm, said latch member being releasably connected to said operating linkage in a manner that the operation of said linkage means in a first direction to actuate said movable contact to open position effects the pivotal movement of said latch to actuate said rocker arm'to move saidblast engaging'rod into displacing engagement with said blast valve to open said blast valve; and, fixed abutment againstwhich said latch member engages after said latch member has been moved to effect the opening of said blast-to effect a release I of said latch member from said operating linkage to' thereby permit said blast valve to return to its normal biased closed position.= I

2. A circuit breaker of thefluid-blast type including I a'hollow stationary contact having first and second crank'5'4'pivots about thepin 56 in a counterclockwise direction, the connecting-rod 53- moves inwardly to move the movable contact 26 to a closed position, as depicted in FIG. 1. Upon complete engagement of the contact 26in the resilient stationary fingers 24, the cam member 71 willhavebeen pivoted in a counterclocka contact 26 and the blast valve 38 and thereafter the release of the blast valve to, reset position is accom- The 'contactand blastvalve arrangement and the operating linkage for effecting the, movement of the contact and the blast valve cooperate to provide a very practical means for arranging a dual back-to-back arrangement of actuating mechanisms which are close coupled for high speed blast valve actuation and which are external of the high pressure gas chamber tank. The mechanism provided does not interfere with the high pressured gas flow'so that adequate flow passages for the high pressure 'gasfrom thetank or from the blast valve is provided. As will be noted, the arrangement providesfor an extremely compact contact and blast valvearrange ment, and onewhich is efficientin itsoperation and has a minimum of operating parts. I

lows:

I The embodiments of the invention tnwhrch an exclu- I sive property or privilege is claimed are defined as folopenings therein;

a movable contact adapted to close said first opening in said stationary contact when engaged therewith and being separable from saidstationary contact to establish an=arc; I

a source of fluid under pressure; I

fluid passage means operably connected between said source of fluid under-pressure and an area adjacent said firstopening where thearc is established;

said fluid passage means being constructediand armeans, said blast valve being normally biased-to a closed position to prevent the flowof fluid; under 3 pressure from said source through said passage means; I I, 3

a blast valve. rocker arm pivotally supported for movement into forceful engagement with said blast valve to displace said blast valve to open position;

- operating linkage operably connected to move said movable contact to open position; i a drive member connected to said blast valve opening arm and to said operating linkage, said drive memberhaving-a 'displaceable releasing element for effecting the release of said drive member from said operating linkage, said drive means being operable upon the operation of said operating linkage in a direction to effect the movement of said movable contact to its open position to move said rocker arm into forceful engagement with said blast valve to displace said blast valve to open position; and,

a stationary abutment disposed in the path of travel of said drive member in position to engage said displaceable releasing element thereof to effect the release of said drive member from'said operating linkage after said blast valve has been displaced to open position and prior to said operating linkage moving said movable. contact to its full open position;

whereby said blast valve is biased to its closed position prior to said movable contact being actuated fully open.

3. A circuit breaker according to claim 2 wherein said drive member includes a body portion pivotally supported for movement on a blast valve opening movement by said operating linkage,said body portion having'a bore therein; I

and said. displaceable releasing element is a latch carried with the bore of said body portion and braised outwardly thereof; v

a-cam member'conn'ected to actuate by said operating linkage for movement in apath of travel to engaged by said latch for movingsaid latch inwardly into said bore to thereby free said body portion from said operating linkage sothat said blast valve is biased into its normal closed position as said operating linkagec'ontinues to move said movable contact to its full open position,

4. A circuit breake raccording to claim 3 wherein said; cam member is provided with a cam surface en-- gageable with .sai'cl latch to force said body portion through said latch to movebod'ily with said cam member for effecting the operation of said rocker arm for opening said' blast ,yalve assaid operating linkage meansis movingsai'd movable contact to open position.

5. 'Afcircuitbreaker according to claim 4 whereinthere"isfprovided'springmeans'operablyconne cted to urge said body portion'to its. initial positionwhen said latch engages said stationary abutment and is moved inwardly. into the bore of said body portion.

6. An operating arrangement for the synchronous movement of a movable contact open positions; f a

' a frame;

a f rst crank: pivotallysupported on'said fa e; said.

first crank having an operable connection with the contact;

and 'a blast valve to an actuating member pivotally supported on said frame and operably connected to effect opening movement of the blast valve when moved in one direction;

a cam member pivotally supported by said frame and operatively connected to said'first crank to be moved thereby in the same direction;

an abutment on said cam member engageable with said blast valve actuating member to move said actuating member in the one direction as said cam member is moved by said first crank;

means carried by said frame in position to be engaged by said actuating member after said actuating member has effected the opening of said blast valve to effect disengagement of said actuating member from said cam member to thereby free said actuating member for'return movement to its initial position; and,- I

means operably connected to bias said actuating member and said blast valve to their initial positions;

7. An operating arrangement according to claim 6 wherein said actuating member includes a body portion pivotally-supported by said frame;

a resiliently outwardly biased latch carried-by said body portion and extending. outwardly thereof in position to be engaged by said abutment of said cam member as said-cam memberis moved by said first crank; and",

said means engaged by said actuating rnember'after opening of said blast'valv'e being astationary'abut ment against which saidzlatch engages as'said body portion moves with said camfmember, said'latch being moved inwardly into said body..portion;to permit said cam; abutment to pass'jsaid' latch thereby disengaging said; actuating member from said cam member... l

8. In a circuit breaker;

a housing; t

1 an insulated framecarried by saidhousing; 1 y

a hollowstationarycontactlwithin said frame;

a movable tubular contact supported bysaid frame and said source at fluid'under. pres'sure,'sai cl blast valve being normally biased to closed'position; operating linkage means'supported within said housing, said operating'linkage means having an operative connection with said movable contact and beingloperablewhen operated in onedire'ction to move said movablecontact-to'contactjopen posi tion andwhen operated in the opposite'direction to move said movable contactto' contact closed position; e

an actuating member supported within' s aid housing for movement in one'direction from an initial posi tion for displacing said blast valve to an open position, said actuating member having an operative mechanical connection with said blast valve;

a cam member pivotally supported by said housing and operably connected to be moved in its path of travel by said operating linkage means, said cam v member being disposed in position to engage said actuating member when moved in its path of travel to thereby move said actuating member with it in its one direction to effect displacement of said blast valve as said operating linkage means operates to move said movable contact to contact open position; 1

means to disengage said actuating member from said cam member after said blast valve has been displaced to open position and prior to said movable contact being moved to full contact open position to thereby free said actuating member to return to its initial position and to permit said blast valve tobe biased to its normally closed position; biasing means operably connected to urge said actuating member to its initial position; and, an operator connected to effect the operation of said operating linkage means. I 9. In a circuit breaker including an enclosure containing a dielectric fluid at a firstpressure;

a source of said dielectric'fluid at a second higher pressure; means operable when actuated for establishing an arc in an area in the dielectric fluid at the first pressure;

means interconnecting said source of dielectric fluid at the second pressure to the areain which the arc is established in the dielectric fluid at the first pressure;

a blast valve interposed between said interconnecting 1 said operating means completing theactuation of said means for establishing the arc. 10. A circuit breaker including an enclosure; means forming a pressure chamber and containing a dielectric fluid under pressure; I i means operable when actuated to establish an arc in an area within said enclosure; means defining a fluid directing passage between said pressure chamber and the area in which said are is established; I displaceable means normally operating to confine the fluid'under pressure in said pressure chamber;

operating means operable to actuate said means to establish anfarc'and to efiect the mechanical displacement of said displaceable means 'which con- 6 fines the fluid under pressure in said pressure chamber in synchronism to thereby provide dielecblast valve is biased to its normal position prior to tric fluid under pressure to the area of the arc to effect extinction of the arc; and,

means operable to disassociate said operating means from said displaceable means to allow said displaceable means to return to its normal position to thereby close off the flow of the dielectric fluid from said pressure chamber.

11. A circuit breaker including an enclosure;

means forming a pressure chamber and containing a dielectric fluid under pressure; 1

a pair of hollow contacts one of which is movable to establish an arc therebetween in an area in said enclosure;

means defining a fluid directing passage around said movable contact to the area wherein an arc is established, said means being in communication with said pressure chamber;

displaceable means normally operating to confine the fluid under pressure in said pressure chamber;

operating means mechanically connected to move said movable contact to contact open position to establish an arc, said operating means being further mechanically connected and to effect the displace ment of said displaceable means to release said dielectric fluid under pressure from said pressure chamber to thereby provide a blast of the dielectric fluid to the area of the arc to extinguish the arc, said blast of dielectric fluid exhausting through both of said hollow contacts into said enclosure;

and, l l i a means to render said operating means mechanically inoperative with respect to saiddisplaceable means to therebypermit said displaceable means to return to its normal position to thereby close said pressure chamber to prevent the flow of the fluid under pressure therefrom.' 5 I 12. A'circuit breaker including an enclosure; a pressure tank connected to said enclosure and containing a dielectric fluid under pressure; an insulated housing within said enclosure; a pair of contacts in said housing one of which is movable to: establish-an arc therebetween in an termediate flow passage connection between said' pressure tank and the portion of the'passage surrou'ndingfsaid movable contact which does not interfere with the movement of said movable contact orthe opening through the movable contact;

' a valve means'operably interposed between said pressure tank and said passage means, said valve means being normally biased to a closed position to block the flow of fluid from said pressure tank; operating means within said enclosure and operably connected to move said contact to'open position to, thereby establish an arc, said connection being made at the end of said movable contact through the arc; and,

the P of Said means definmg the fluid flow means to effect disassociation" of said operating passage h' movable f means from said valve to allow said valve means to said operating means having an operable association with said valve means to open said valve means return to normal posmon pnor to Sald operating in synchronism with the opening movement of said means moving said movable Contact to fully open said movable contact to thereby provide a blast of p fluid under pressure to the arcing area to extinguish I 

1. A circuit breaker of the fluid-blast type including a stationary contact; a movable contact separable from said stationary contact to establish an arc; a source of fluid under pressure; a blast valve operably connected between said source of fluid under pressure and the area where an arc is drawn between said contacts, said blast valve being normally biased to a closed position, and operable when mechanically actuated to an open position to direct a blast of fluid under pressure to the area of arcing; a frame; a rocker arm pivotally supported by said frame; a blast valve engaging rod carried by said rocker arm in position to engage and displace said blast valve to an open position when said rocker arm is pivoted in one direction; operating linkage means operably connected to move said movable contact to open position; a pivotal latch member operably connected to said rocker arm, said latch member being releasably connected to said operating linkage in a manner that the operation of said linkage means in a first direction to actuate said movable contact to open position effects the pivotal movement of said latch to actuate said rocker arm to move said blast engaging rod into displacing engagement with said blast valve to open said blast valve; and, a fixed abutment against which said latch member engages after said latch member has been moved to effect the opening of said blast to effect a release of said latch member from said operating linkage to thereby permit said blast valve to return to its normal biased closed position.
 2. A circuit breaker of the fluid-blast type including a hollow stationary contact having first and second openings therein; a movable contact adapted to close said first opening in said stationary contact when engaged therewith and being separable from said stationary contact to establish an arc; a source of fluid under pressure; fluid passage means operably connected between said source of fluid under pressure and an area adjacent said first opening where the arc is established; said flUid passage means being constructed and arranged with its outlet surrounding said movable contact whereby a blast of fluid under pressure is directed to the area of the arc between said housing and said movable contact; deflector means carried by said stationary contact at the area where the arc is established to deflect the blast of fluid radially inwardly so that the blast of fluid is concentrated directly at the arc established between the contacts; a blast valve operably interposed between said source of fluid under pressure and said fluid passage means, said blast valve being normally biased to a closed position to prevent the flow of fluid under pressure from said source through said passage means; a blast valve rocker arm pivotally supported for movement into forceful engagement with said blast valve to displace said blast valve to open position; operating linkage operably connected to move said movable contact to open position; a drive member connected to said blast valve opening arm and to said operating linkage, said drive member having a displaceable releasing element for effecting the release of said drive member from said operating linkage, said drive means being operable upon the operation of said operating linkage in a direction to effect the movement of said movable contact to its open position to move said rocker arm into forceful engagement with said blast valve to displace said blast valve to open position; and, a stationary abutment disposed in the path of travel of said drive member in position to engage said displaceable releasing element thereof to effect the release of said drive member from said operating linkage after said blast valve has been displaced to open position and prior to said operating linkage moving said movable contact to its full open position; whereby said blast valve is biased to its closed position prior to said movable contact being actuated fully open.
 3. A circuit breaker according to claim 2 wherein said drive member includes a body portion pivotally supported for movement on a blast valve opening movement by said operating linkage, said body portion having a bore therein; and said displaceable releasing element is a latch carried with the bore of said body portion and braised outwardly thereof; a cam member connected to actuate by said operating linkage for movement in a path of travel to engage the end of said latch extending outwardly of said bore of said body portion to thereby effect the movement of said body portion and thereby the operation of the blast valve rocker arm for opening said blast valve; and, stationary abutment means disposed in the path of travel of said body portion in position to be engaged by said latch for moving said latch inwardly into said bore to thereby free said body portion from said operating linkage so that said blast valve is biased into its normal closed position as said operating linkage continues to move said movable contact to its full open position.
 4. A circuit breaker according to claim 3 wherein said cam member is provided with a cam surface engageable with said latch to force said body portion through said latch to move bodily with said cam member for effecting the operation of said rocker arm for opening said blast valve as said operating linkage means is moving said movable contact to open position.
 5. A circuit breaker according to claim 4 wherein there is provided spring means operably connected to urge said body portion to its initial position when said latch engages said stationary abutment and is moved inwardly into the bore of said body portion.
 6. An operating arrangement for the synchronous movement of a movable contact and a blast valve to open positions; a frame; a first crank pivotally supported on said frame, said first crank having an operable connection with the contact; an actuating member pivotally supported on said frame and operably connected to effect opening movement of the blast valve wHen moved in one direction; a cam member pivotally supported by said frame and operatively connected to said first crank to be moved thereby in the same direction; an abutment on said cam member engageable with said blast valve actuating member to move said actuating member in the one direction as said cam member is moved by said first crank; means carried by said frame in position to be engaged by said actuating member after said actuating member has effected the opening of said blast valve to effect disengagement of said actuating member from said cam member to thereby free said actuating member for return movement to its initial position; and, means operably connected to bias said actuating member and said blast valve to their initial positions.
 7. An operating arrangement according to claim 6 wherein said actuating member includes a body portion pivotally supported by said frame; a resiliently outwardly biased latch carried by said body portion and extending outwardly thereof in position to be engaged by said abutment of said cam member as said cam member is moved by said first crank; and, said means engaged by said actuating member after opening of said blast valve being a stationary abutment against which said latch engages as said body portion moves with said cam member, said latch being moved inwardly into said body portion to permit said cam abutment to pass said latch thereby disengaging said actuating member from said cam member.
 8. In a circuit breaker; a housing; an insulated frame carried by said housing; a hollow stationary contact within said frame; a movable tubular contact supported by said frame for axial movement into and out of contact closed and open position relative to said stationary contact; a fluid passage surrounding said movable contact and terminating at an area adjacent the ends of said contacts where an arc is established; a source of fluid under pressure carried by said housing; fluid passage means formed in said frame interconnecting said fluid passage surrounding said movable contact and said source of fluid under pressure; a blast valve interposed in said fluid passage means and said source of fluid under pressure, said blast valve being normally biased to closed position; operating linkage means supported within said housing, said operating linkage means having an operative connection with said movable contact and being operable when operated in one direction to move said movable contact to contact open position and when operated in the opposite direction to move said movable contact to contact closed position; an actuating member supported within said housing for movement in one direction from an initial position for displacing said blast valve to an open position, said actuating member having an operative mechanical connection with said blast valve; a cam member pivotally supported by said housing and operably connected to be moved in its path of travel by said operating linkage means, said cam member being disposed in position to engage said actuating member when moved in its path of travel to thereby move said actuating member with it in its one direction to effect displacement of said blast valve as said operating linkage means operates to move said movable contact to contact open position; means to disengage said actuating member from said cam member after said blast valve has been displaced to open position and prior to said movable contact being moved to full contact open position to thereby free said actuating member to return to its initial position and to permit said blast valve to be biased to its normally closed position; biasing means operably connected to urge said actuating member to its initial position; and, an operator connected to effect the operation of said operating linkage means.
 9. In a circuit breaker including an enclosure containing a dielectric fluid at a first pressure; a source of said dielectric fluid At a second higher pressure; means operable when actuated for establishing an arc in an area in the dielectric fluid at the first pressure; means interconnecting said source of dielectric fluid at the second pressure to the area in which the arc is established in the dielectric fluid at the first pressure; a blast valve interposed between said interconnecting means and said source and normally operating to prevent the fluid at the second pressure from flowing into said interconnecting means; mechanically connected operating means for actuating in timed relationship said means for establishing an arc and displacing said blast valve from its normal position to thereby provide a blast of dielectric fluid at the second higher pressure at the area where said arc is established to extinguish the arc; and, means to disengage said blast valve from said mechanically connected operating means so that said blast valve is biased to its normal position prior to said operating means completing the actuation of said means for establishing the arc.
 10. A circuit breaker including an enclosure; means forming a pressure chamber and containing a dielectric fluid under pressure; means operable when actuated to establish an arc in an area within said enclosure; means defining a fluid directing passage between said pressure chamber and the area in which said arc is established; displaceable means normally operating to confine the fluid under pressure in said pressure chamber; operating means operable to actuate said means to establish an arc and to effect the mechanical displacement of said displaceable means which confines the fluid under pressure in said pressure chamber in synchronism to thereby provide dielectric fluid under pressure to the area of the arc to effect extinction of the arc; and, means operable to disassociate said operating means from said displaceable means to allow said displaceable means to return to its normal position to thereby close off the flow of the dielectric fluid from said pressure chamber.
 11. A circuit breaker including an enclosure; means forming a pressure chamber and containing a dielectric fluid under pressure; a pair of hollow contacts one of which is movable to establish an arc therebetween in an area in said enclosure; means defining a fluid directing passage around said movable contact to the area wherein an arc is established, said means being in communication with said pressure chamber; displaceable means normally operating to confine the fluid under pressure in said pressure chamber; operating means mechanically connected to move said movable contact to contact open position to establish an arc, said operating means being further mechanically connected and to effect the displacement of said displaceable means to release said dielectric fluid under pressure from said pressure chamber to thereby provide a blast of the dielectric fluid to the area of the arc to extinguish the arc, said blast of dielectric fluid exhausting through both of said hollow contacts into said enclosure; and, means to render said operating means mechanically inoperative with respect to said displaceable means to thereby permit said displaceable means to return to its normal position to thereby close said pressure chamber to prevent the flow of the fluid under pressure therefrom.
 12. A circuit breaker including an enclosure; a pressure tank connected to said enclosure and containing a dielectric fluid under pressure; an insulated housing within said enclosure; a pair of contacts in said housing one of which is movable to establish an arc therebetween in an area within said housing, said movable contact being tubular with one end extending outwardly of said housing into said enclosure when moved to contact open position; means defining a fluid flow passage extending between said pressure tank and the arcing area within said housing, a portion of said means defining said Fluid flow passage surrounding said movable contact, said means defining said passage also, having a portion thereof extending angularly from the portion which surrounds said movable contact, said angular extending portion having a U-shaped configuration in cross-section thereby providing an intermediate flow passage connection between said pressure tank and the portion of the passage surrounding said movable contact which does not interfere with the movement of said movable contact or the opening through the movable contact; a valve means operably interposed between said pressure tank and said passage means, said valve means being normally biased to a closed position to block the flow of fluid from said pressure tank; operating means within said enclosure and operably connected to move said contact to open position to thereby establish an arc, said connection being made at the end of said movable contact through the portion of said means defining the fluid flow passage which surrounds said movable contact, said operating means having an operable association with said valve means to open said valve means in synchronism with the opening movement of said said movable contact to thereby provide a blast of fluid under pressure to the arcing area to extinguish the arc; and, means to effect disassociation of said operating means from said valve to allow said valve means to return to its normal position prior to said operating means moving said movable contact to fully open position. 